One of my favourite things about ACforums is the attention paid to scientific facts and not myths that have existed for way too long.
It really isn't surprising that people believe it unsafe to change more than 30% of their water weekly, after all, even gravel vacs have "Don't change more than 1/3 of the water" on the box!
I think that the debate has essentially drawn to a close and any more comments on one side or another will not further clarify anything. However, I do believe that something of this nature is extremely informative because of the amount of factual information and science involved. A great deal was covered, from the nature of nitrifiers to a healthy dose of skepticism towards written material, especially anything based on anecdote. Someone can keep fish for many years and not really know what's going on in the tank or filter, do the sheer number of years qualify them to publish aquaria info? IMO, no, but I have a tendancy to not believe anything until it's proved to me unless of course the statement already jives with my existing knowledge. In any rate, I think that the thread itself would be a good read for a newbie with a discerning eye.
On another note, what are the Title and Author(s?) of this book?